Dysphagia is a phenomenon that arises from diffi-culties in the process of swallowing materials, commonly observed in patients with cervical spinal cord injury. Kirshblum et al.¹ reported that 22.5% of patients with spinal cord injury complained of dysphagia, and 73.8% of them were confirmed by a videofluoroscopic swallowing study (VFSS). In a study by Hayashi et al.², severe dysphagia occurred in 7% of patients with cervical spinal cord injury. Predictive factors for the occurrence of dysphagia in patients with spinal cord injury include age, a history of tracheostomy, surgical approach (anterior or not), mechanical ventilation, and the extent of neurological impairment^1,3.

A comprehensive approach, including nutritional support, rehabilitation techniques, and compensation strategies, is necessary for managing dysphagia. Without appropriate interventions, various complications can arise, ranging from nutritional deficiencies and dehy-dration to pneumonia⁴, along with a spectrum of psychiatric and neurological issues, including depression and cognitive impairment⁵. Especially in patients with spinal cord injury, pneumonia is the leading cause of mortality. It is known that there is a higher incidence of respiratory diseases as the level of spinal cord injury increases⁶. Proper management of dysphagia according to its etiology is crucial to prevent aspira-tion and reduce the risk of respiratory complications.

The pathophysiology of dysphagia in patients with cervical cord injury has not been identified³. However, numerous risk factors in patients with cervical cord injury can contribute to the development of dysphagia. The spinal cord injury itself may contribute to dys-phagia, as damage to the glossopharyngeal, vagus, or hypoglossal nerves, which are crucial for the swallo-wing reflex, can occur due to brainstem compression induced by cervical cord injury⁷. Additionally, secondary dysphagia may result from various complications arising after cervical spine surgery⁸. Reports also suggest the occurrence of dysphagia due to structural damage involving the nerves and muscles around the neck⁹.

Therefore, when treating dysphagia in patients with cervical cord injury resulting from cervical spine sur-gery, it is crucial to consider the various potential causes. Accurately identifying the underlying causes of dysphagia is essential for appropriate treatment. Prior to initiating treatment, a comprehensive evaluation, including imaging studies such as VFSS to assess the overall swallowing process or fiberoptic endoscopic evaluation of swallowing (FEES) to identify structural abnormalities, along with a thorough review of the patient’s medical history, inquiry about accompa-nying symptoms, and a precise physical examination, should be conducted⁴.

In this case report, we describe two cases where dysphagia occurred as a secondary complication due to postoperative issues rather than as a typical com-plication following cervical spine surgery. The purpose is to highlight instances where dysphagia arises as a secondary consequence of postoperative complications rather than being a direct complication of the cer-vical spine surgery itself.

1. Case #1

A 60-year-old male patient, who had history of falling forward while riding a bicycle which caused retrolisthesis at C3/4 and receiving C3/4 anterior cervical discectomy and fusion was admitted to our hospital three months after the initial injury. His tracheostomy was already decannulated before admi-ssion to our hospital. Two months after admission, the patient developed left chin pain and swelling, and a neck computed tomography (CT) was performed to reveal severe parotitis and mild hypophayngitis (Fig. 1). The patient was started on antibiotics, and the swelling and pain of left parotid gland decreased. After three weeks, the patient complained of swallo-wing pain. A follow-up neck CT confirmed improve-ment in parotitis but showed diffuse hypopharyngitis and proximal esophagitis (Fig. 2A, B). Intravenous antibiotics were administered again. VFSS demonstrated delayed swallowing reflex, incomplete laryngeal elevation and liquid penetration scoring 2 points on the Pene-trationAspiration Score (PAS). No abnormal findings were observed on laryngoscopy, and endoscopy showed no prominent esophagitis or esophageal fistula.

Figure 1. Neck CT performed to evaluate left chin swelling. (A) Axial image showing severe swelling of left parotid gland (arrow). (B) Axial image representing mild mucosal thickening of left hypopharynx (arrow). (C) Sagittal image showing hypopharynx and retropharyngeal space.

Figure 2. Neck CT showing hypopharynx and retropharyngeal area. (A) Axial image demonstrating hypopharyngitis (arrow). (B) Sagittal image showing hypopharyngitis (arrow). (C) Neck CT of 2-week follow stu-dy showing retropharyngeal edema (arrow). (D) Sagittal image of 2-week follow study Neck CT shows progressed state of diffuse retropharyngeal edema (arrow).

While hypopharyngitis improved after four weeks of sufficient intravenous antibiotic therapy, the patient continued to complain of odynophagia. Also, he developed fever, and the laboratory tests showed increased C reactive protein. Neck CT demonstrated diffuse retropharyngeal edema and prevertebral fat stranding with multifocal air densities from 4th to 7th cervical spines (Fig. 2C, D). Because the patient had received anterior cervical spine fusion (ACSF) due to cervical cord injury, C-spine magnetic resonance ima-ging (MRI) was done to evaluate hardware infection. The C-spine MRI showed deep neck infection at levels from 4th to 7th cervical spines (Fig. 3). In con-sultation with the orthopedic department, implant in-fection was thought to be ruled out. Instead of surgical treatment, the antibiotic regimen was adjus-ted, and intravenous antibiotics were administered based on the deep neck infection. Since then, the patient’s swallowing pain has improved significantly, and inflammatory markers have returned to normal levels.

Figure 3. MRI of cervical spine suggesting deep neck infection. (A) Sagittal T2 weight enhanced image showing edema and soft tissue enhancement of prevertebral space of C4 to C7 (arrow). (B) Axial T2 image presenting prevertebral soft tissue enhancement and bone marrow edema at C5 level.

2. Case #2

A 73-year-old female patient underwent cervical cord injury from a fall during hiking and ACSF was performed at the C3/C4 levels. Attempts to resume an oral diet during intensive care resulted in an incident suggestive of aspiration. Nasogastric tube feeding was maintained until four months after the initial injury, and a tracheostomy was performed. At that point, a VFSS revealed a delayed swallowing reflex, incomplete closure of the velopharyngeal port, and post-swallowing aspiration with large liquid, scoring 7 points on the PAS (Fig. 4A).

Figure 4. Changes in VFSS before and after rehabilitation for dyspha-gia. (A) VFSS before rehabilitation showing large liquid aspiration sco-ring 7 points on the PAS (arrow). (B) VFSS after rehabilitation showing large liquid penetration scoring 2 points on the PAS (arrow).

After one month of oromotor facilitation for dys-phagia confirmed by the VFSS, a follow-up study revealed improved findings. Penetration was observed with liquid and semisolid consistency, scoring 2 points on the PAS (Fig. 4B), but definitive signs of aspiration were not noted. Consequently, the introduction of oral intake for swallowing practice began with a gel-like diet at the first stage of dysphagia. However, the patient reported throat discomfort shortly after initiation, leading to diet discontinuation. Subsequently, symptoms suggestive of aspiration, such as coughing and phlegm, emerged. In follow-up VFSS, aspiration was not obse-rved, and no significant interval changes were noted compared to previous examinations. Laryngoscopic examinations did not reveal any abnormalities. Eso-phagogastroduodenoscopy indicated resistance during upper esophageal sphincter passage with some impair-ment in relaxation, but no diverticulum or other struc-tural problems were observed. Nevertheless, even after the examination, the patient continued to complain of discomfort and pain with attempts at dietary intake exceeding a spoonful for therapeutic purposes.

Therefore, it was determined that a swallowing dis-order occurred during oral intake above a certain level, and a C-spine CT was performed. The CT revealed findings suggestive of hardware loosening (Fig. 5). In consultation with orthopedic department, there was a suggestion that the affected area might be contri-buting to dysphagia, and it was acknowledged that reoperation could potentially correct the symptoms. However, considering the patient’s age, underlying ge-neral condition, and the findings in the initial surgery, the risks associated with reoperation were deemed high, and reoperation was not attempted. Consequently, oral intake was not attempted except for therapeutic purposes, and tube feeding was maintained.

Figure 5. Cervical spine CT suggesting loosening of hardware at C3-4 levels. (A) Axial image at C3 level. (B) Axial image at C4 level. (C) Sagittal image.

The case report describes two patients experiencing dysphagia after cervical cord injury, suspected to be a complication of anterior approach cervical surgery. According to Kim et al.¹⁰, approximately 5.8% of cases reported failure after this surgery, with most showing symptoms between 1 and 3 months after the procedure. The predominant clinical symptom was neck pain, and dysphagia accounted for 14.3%. This rate is comparable to the reported rates of dysphagia as a postoperative complication after ACSF, ranging from 17.8% to 19.4% in other studies^11,12. These findings suggest challenges in distinguishing whether dysphagia reported after anterior approach cervical surgery is due to surgical failure or if symptoms occur despite successful completion.

According to Lee et al.¹³, risk factors for developing dysphagia following anterior cervical spine surgery include gender, multilevel involvement, and revision surgeries. It is essential to consider these risk factors in postoperative management. Complications such as adjacent segment disease (8.1%), C5 paralysis (3.0%), hematoma (1.0%), esophageal perforation (0.2%), and others⁸, which can occur post-surgery, should also be taken into account. Furthermore, it should be noted that the incidence of dysphagia, particularly within the first six weeks after surgery, is reported to be 5-6 times higher compared to posterior cervical spine surgery¹⁴. In the two cases of dysphagia presented, the absence of risk factors, except for gender, adds clinical significance to the understanding of posto-perative dysphagia.

In both cases, complications related to anterior cervical spine surgery are suspected, but the therapeutic approaches are entirely different. In the first patient, dysphagia is presumed to have occurred due to se-vere neck infection, and symptomatic improvement was observed after intravenous antibiotic admini-stration. In the second patient, it was presumed that swallowing difficulty occurred due to hardware loose-ning. Although not performed, reoperation could be considered with the expectation of symptom impro-vement. If the cause of dysphagia was solely attributed to surgery as a primary complication, rehabilitation for dysphagia was implemented, and the symptoms worsened. Therefore, to determine the appropriate treatment, it is crucial to consider the possibility that dysphagia may have arisen as a secondary complication and conduct an evaluation accordingly. This highlights the importance of a comprehensive assessment, consi-dering potential secondary complications, to ensure the most suitable therapeutic approach.

Moreover, caution is warranted regarding the diag-nosed deep neck infection in the first case. A deep neck infection refers to a pathology arising from the spread of inflammation in the neck space through blood vessels, lymphatic vessels, or direct pathways. The area is a surgical space that is typically accessed during upper cervical surgery, and overall wound in-fection rates after ACSF are generally reported to be low, around 0.1%¹⁵, mainly occurring in the early postoperative period¹⁶. In this case, although the deep neck infection did not occur during the com-monly observed early postoperative period, the site of infection overlapped with the area accessed during the previous spinal surgery, and no other events could have caused the infection. Considering this, it is highly likely that this infection, though uncommon, is a late postoperative complication. There are some reports of dysphagia caused by deep neck infection¹⁷, so if a swallowing disorder occurs, it is necessary to distinguish whether it is a symptom of the infection. This complication demands attention as it may lead to fatal consequences if left untreated¹⁵. Late-onset deep neck infections after cervical spine surgery are often linked to severe complications such as esopha-geal perforation, implant migration, and Zenker’s dive-rticulum, underscoring the need for careful monitoring in the late postoperative period^18,19. Therefore, vigilant observation is crucial for late-onset dysphagia follo-wing cervical spine surgery.

Cases where issues with surgical hardware, as ob-served in the second patient, also need to be careful. Particularly, when hardware is inserted through cervical surgery, the condition itself can potentially induce dysphagia. However, this symptom typically improves over time, with only about 5% reporting moderate to severe dysphagia six months or more after surgery¹². In cases of severe dysphagia persisting for more than six months, insertion of a nasogastric tube or a per-cutaneous endoscopic gastrostomy tube is generally considered for improving quality of life and ensuring nutritional stability. However, in cases of severe dys-phagia, consideration should be given to the possi-bility of surgical failure. If failed surgery is confirmed, the removal of the hardware can also be considered under the condition that the spine’s stability is secu-red²⁰. Notably, there is a report where the removal of hardware resulted in the improvement of dysphagia suspected to be caused by hardware placement²⁰. In cases of severe dysphagia in patients with cervical cord injury, it is important to appropriately follow up on the surgical site through cervical spine CT to discern whether the issue is induced by problems at the surgical site.

These cases emphasize the importance of distingui-shing between primary and secondary dysphagia as a postoperative complication. Dysphagia significantly impacts the quality of life in patients with cervical cord injury, necessitating appropriate therapeutic app-roaches. However, identifying the precise cause is challenging due to predisposing factors such as the tracheostomy state and old age. The report presents that in cases where postoperative complications, such as deep neck infection or hardware loosening, result in secondary dysphagia, targeted interventions can effectively address and correct dysphagia. Considering various risk factors when approaching dysphagia during postoperative management not only aids in devising treatment strategies but also assists in diffe-rentiating postoperative complications.

The authors declare no conflict of interest.

This research received no external funding.

The case report received an exemption determi-nation from the Institutional Review Board of National Health Insurance Service Ilsan Hospital.